These biological safety cabinets are designed to discharge HEPA-filtered exhaust air directly into the laboratory, or into an exhaust system through the optional Canopy Connection. When canopy-connected, the biosafety cabinets may be used for applications involving minute quantities of volatile toxic chemicals and tracer amounts of radionuclides as an adjunct to microbiological research.

During operation, room air is drawn into the inlet grill. The air in the plenum beneath the work surface is a mixture of unfiltered room airand air that has just passed through the work area. This contaminated air is drawn by the blower through the back plenum of the cabinet, where approximately 70% of the air is recirculated through the supply HEPA filter and back over the work area. The balance of the contaminated air is discharged to the environment after passing through the exhaust HEPA filter.

It is written to assist the end-user in validation of predetermined specifications. The protocol begins with planning the site for the piece of equipment and therefore is of value prior to receipt of delivery.